Milestone Pharmaceuticals, a clinical-stage cardiovascular company, announced that the first patient has been randomised in its phase 3 clinical study of etripamil. Etripamil is a new investigational, rapid-onset, short-acting calcium channel blocker administered intranasally by the patient designed to terminate paroxysmal supraventricular tachycardia (PSVT) episodes wherever they occur. PSVT is a recurring and sporadic heart arrhythmia caused by abnormalities in the cardiac conduction system. The current standard of care to terminate these episodes is intravenous medication delivered in the emergency department.

The phase 3, multicentre, randomised, double-blind, placebo-controlled, event-driven study is planned to be conducted in more than 50 cardiology centres in the United States and Canada and will enrol up to 500 patients. Following an in-office test dose of etripamil, patients will take home either 70mg of etripamil or placebo for when a PSVT episode occurs. Upon onset of an episode, patients will apply a wireless cardiac monitor to their chest to record their heart rhythm, perform a vagal manoeuvre, and if symptoms persist, administer study drug.

“The design of the NODE-301 study of etripamil will allow us to obtain more clinical evidence of the benefits of this potential treatment for PSVT in an outpatient, real-world setting,” said Bruce Stambler, Piedmont Heart Institute, Atlanta, USA. “PSVT is an unpredictable disorder and the potential for a fast-acting therapy to resolve the symptoms of PSVT wherever the episodes occur could significantly reduce the burden this condition puts on patients and the healthcare system.”

The primary endpoint of the NODE-301 study is time to conversion of PSVT to sinus rhythm after the administration of study drug as confirmed by a central independent adjudication committee. Secondary study endpoints include relief of symptoms commonly associated with an episode of PSVT such as heart palpitations, chest pain, anxiety, shortness of breath, dizziness, and fainting.

“The initiation of the NODE-301 study is an example of our ongoing commitment to improve the lives of patients with PSVT,” said Francis Plat, Milestone’s chief medical officer. “Etripamil, if approved by regulatory authorities, could empower patients to take control of this anxiety-producing arrhythmia without being reliant on chronic medications or trips to an acute-care facility for treatment.”

The study will enrol patients at least 18 years of age with a documented history of PSVT. Patients receiving study treatment in NODE-301 will be eligible to participate in an open-label extension study (NODE-302) where etripamil will be provided for subsequent PSVT episodes.

“There are well over a million people in the USA living with PSVT, resulting in hundreds of thousands of emergency department and doctor’s office visits each year,” said Eileen Handberg, research professor of medicine at the University of Florida, Gainesville, USA. “In addition, countless other patients exist who don’t seek care and suffer through their episodes in silence as the current approved treatment options are unpleasant, inconvenient, and/or costly. Providing a way to self-manage PSVT episodes could offer immediate relief for those living with this arrhythmia.”